TV REVIEW The ghost train to Philadelphia… without the train

THE ONE WHERE Stuck in a tunnel and low on air, the gang starts to hallucinate as it enter the city.

VERDICT It's the calm before the storm with plenty of character moments, but not so much action as the Matheson gang heads into the train tunnels under Philadelphia to get to the city.

Meeting a rebel group outside on the outskirts, Miles makes a deal to give them access to Sebastian Monroe if they help get the gang through the tunnel network, the city now defended by 30 foot high walls all around.

Nora reveals to Charlie that Miles tried to kill Sebastian before he left the militia, but couldn't bring himself to do it. The two girls chat and walk until Charlie steps on a landmine. Doh. I'm no expert but when I'm out walking with friends I find it usual for the folk who want a good natter to gravitate toward the back of the group, while the ones at the front tend to look where they're going. Charlie quickly learns another lesson that even I thought would have been a bit obvious: a guarded tunnel into a fortified city probably has traps in it. In her defence though, I learned that playing computer games, so I'll give the benefit of the doubt for not having that pleasure. Thanks to Nora she's saved fro being blown to bits, but the explosion brings down the tunnel walls, which leads to their next problem as the oxygen slowly runs out and one-by-one the members of the gang begin to hallucinate their own worst demons. Aaron is plagued by the guilt of his wife who he left behind. Nora imagines an alligator in a scene reminiscent of the trash compactor in Star Wars: A New Hope .

A great turn this week from Billy Burke as Miles, playing to his strengths as world weary and a bit battered, a man just after an easier life. He knows he's hallucinating when he wanders off track into a warm glowing office of Sebastian Monroe, meeting him again. The conjurer Bass makes Miles face up to his “dirty little secret”; Miles is conflicted and unconvinced that the gang will be able to save Danny or get out of Philadelphia alive. As a voice in his head, Bass sounds off Miles' darkest doubts – he's prepared to sell out on all his new friends and family, even rejoin the militia to save his own bacon. On returning to the group he's a bit rattled, and Charlie gives him a verbal slap to get it together.

Meanwhile, inside the city Rachel is the not-so-happy owner of a magic pendant and has been tinkering with the inside of a washing machine for weeks… or that's what it looks like. We find out it’s actually a signal booster to enable Monroe's Army to mobilise some weapons – or is it? A second opinion from her poor bedraggled ex-college Brad reveals it's actually a bomb. Monroe naturally goes a bit mental on her, explaining she's not indispensable now as he has Brad, so Rachel shivs Brad in the guts. Poor bugger Brad. We only only knew him briefly.

Revolution as a habit of killing off new characters. You can usually tell the difference between a guest star and a new arrival, but this show has a habit of giving us someone we've never seen before, providing them with a little slice of screen time and a bit of exposition to suggest to genre-savvy viewers that they're being seeded in and not simply a “red-shirt”, tagged for a quick exit. Then they get a quick exit. Case in point this week is Ashley, a young rebel lass who's a great shot with a bow. In a short scene with Aaron she explains why she's fighting for the United States, even though she's too young to really know what that means… and then she's shot dead by a double crossing rebel leader.

Charlie seeks swift revenge, killing the undercover militia man, but is shot herself. A very lucky point blank range glancing shot off the forehead, complete with not very convincing blood smear, sends her into deep unconsciousness where she dreams of her dad, Ben, and the comforts of home. Ben tells her to lie back and rest, while back back in the real world Uncle Miles is desperately trying to bring her back around. After Miles’s doubts about his own conviction, the possibility of losing Charlie is the real slap around the face he needs. His attempt to revive Charlie is an affirmation that when the chips are down, in the season finale next week, he'll probably do the right thing. Lets hope.

UNFORTUNATE VICTIM OF THE WEEK Poor Ashley, but poorer scientist Brad. He was a member of the team who made the magic pendants. Beaten, tortured then stabbed by a co-worker.

WHAT HAPPENED TO? Danny Matheson. He's the reason everyone's in jeopardy and we've not seen him for two weeks.

W HAT'S THAT SONG? Both songs in this episode are by Led Zeppelin. “Since I’ve Been Loving You” is playing on the radio, and “Kashmir” is also the title of the episode.

BEST LINE Aaron: “You're 19 and fighting for the United States. Do you even remember the United States?”